Reporting Segments (Details) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				2
Net Sales by Reporting Segment
Net sales		$ 2,492.0	$ 2,478.0	$ 7,609.0	$ 7,956.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		341.0	346.0	1,038.0	1,142.0
Restructuring expense		14.0	5.0	41.0	44.0
Merger, acquisition and divestiture expense		4.0	2.0	10.0	5.0
Other expense (income), net		0.0	2.0	14.0	(3.0)
Officer stock awards modification		0.0	6.0	2.0	2.0
Corporate, including stock-based compensation		47.0	53.0	146.0	170.0
Equity in affiliates’ earnings, net of tax		(7.0)	(15.0)	(25.0)	(38.0)
Interest income		(4.0)	(1.0)	(9.0)	(4.0)
Interest expense		15.0	14.0	43.0	45.0
Other postretirement (income) expense		(1.0)	(3.0)	26.0	(8.0)
Earnings before income taxes and noncontrolling interest		273.0	283.0	790.0	929.0
Provision for income taxes		66.0	67.0	230.0	192.0
Net earnings		207.0	216.0	560.0	737.0
Net earnings attributable to the noncontrolling interest, net of tax		13.0	12.0	34.0	36.0
Net earnings attributable to BorgWarner Inc.		194.0	204.0	526.0	701.0
Segment Reporting Information - Assets
Total assets		10,199.0		10,199.0		$ 10,095.0
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		8,503.0		8,503.0		8,651.0
Engine [Member]
Net Sales by Reporting Segment
Net sales		1,514.0	1,516.0	4,681.0	4,906.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		241.0	238.0	731.0	797.0
Segment Reporting Information - Assets
Total assets		4,638.0		4,638.0		4,731.0
Drivetrain [Member]
Net Sales by Reporting Segment
Net sales		993.0	976.0	2,973.0	3,093.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		100.0	108.0	307.0	345.0
Restructuring expense					6.0
Segment Reporting Information - Assets
Total assets		3,865.0		3,865.0		3,920.0
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Net sales		(15.0)	$ (14.0)	(45.0)	$ (43.0)
Corporate, Non-Segment [Member]
Adjusted earnings before interest, income taxes and noncontrolling interest
Restructuring expense				3.0
Segment Reporting Information - Assets
Total assets	[1]	$ 1,696.0		$ 1,696.0		$ 1,444.0

[1] Corporate assets include investments and other long-term receivables and certain deferred income taxes.